(a) Field of the Invention
The present invention relates to an improved design of a heating device for a heater fan, particularly a hater fan in which the electric heating coil and the heat insulating plate are mounted and secured on a separate rear mesh disk.
(b) Description of the Prior Art
The operation of a heater fan is based on the principle that a plurality of electric heating coils are provided in the back side of the fan motor inside the heater fan. The electric heating coils generate the heat source which is drawn by the fan motor, thereby delivering warm air to the room.
The electric heating coils in the conventional heater fans are wired around a plurality of heat insulating plates. Such heat insulating plates are mounted in a metal bracket (1) which has a unique shape, as shown in FIG. 1. The metal bracket (1) consists of several supporting legs (11) each one of which is used for clamping an insulating plate (2). The heat insulating plates (2) are then riveted to the supporting legs (11) by rivets. The inside edge of the metal bracket (1) is provided with protruded circular holes (13) which are used for the fan motor to be mounted onto the metal bracket (1). It is obvious that the manufacturing process of this kind of conventional heating device for the heater fan is slow. The heat insulating plates (2) have to be riveted onto the supporting legs (11) first, and then the electric heating coil is then wound around the heat insulating plates (2) before the fan motor is bolted onto the metal bracket (1). Finally, the control wiring of the heater fan can be connected together.
The inventor deeply feels that it is necessary to improve the heating device structure of the heater fan. The reasons for the improvement include the following:
1. Since the structure of the heating device in the conventional heater fan requires the riveting and bolting in the manufacturing process, it is time consuming and slows down the manufacturing pace. PA1 2. The wiring connection of the heating device in the conventional heater fan must be done within the main body of the heater fan. It is, therefore, more difficult to work on and requires a longer time to complete the wiring connection. PA1 3. The main body of a majority of fans are fabricated by injection molding using polystyrene. The area close to the electric heating coils inside the heater fan is generally hot, and therefore, for safety reason, it requires polystyrene that can withstand higher temperature. The high-temperature polystyrene costs more than the general purpose polystyrene, thereby driving the manufacturing cost to be higher. It is a waste because some area in the main body is not affected by the operating temperature of the heater fan.
Therefore, to overcome the aforesaid drawbacks, the Inventor, after years of design and manufacturing experience, has come up with the new improved design of the heating device which has a separated structure.